Cost-Effectiveness of Recombinant Zoster Vaccine for the Prevention of Herpes Zoster in Hematopoietic Stem Cell Transplant Recipients and Other Immunocompromised Adults in the United States.

INTRODUCTION: Immunocompromised (IC) adults are at increased risk of developing herpes zoster (HZ) and HZ-related complications due to therapy or underlying disease. This study evaluated the cost effectiveness of recombinant zoster vaccine (RZV) versus no vaccine for the prevention of HZ in hematopoietic stem cell transplant (HSCT) recipients and other IC adults aged ≥ 18 years in the United States (US). METHODS: A static Markov model simulated cohorts of IC individuals using a 1-year cycle length and 30-year time horizon to estimate the cost effectiveness of RZV. Inputs were sourced from clinical trial results and publicly available sources/literature. Modeled populations included US adult HSCT recipients (base case), patients with human immunodeficiency virus (HIV), patients with breast cancer, patients with Hodgkin's lymphoma, and renal transplant recipients. The model reported societal costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios (ICERs). Sensitivity and threshold analyses were conducted. RESULTS: In the base case of 19,671 US adult HSCT recipients, RZV resulted in total societal cost savings of US$0.1 million and 109 incremental QALYs versus no vaccine. RZV was a 'dominant strategy' versus no vaccine because vaccination resulted in cost savings with QALY gains. RZV was also cost saving in renal transplant recipients, and cost effective at a willingness-to-pay threshold of US$100,000 per QALY gained in patients with HIV, breast cancer, and Hodgkin's lymphoma, with ICERs of US$33,268, US$67,682, and US$95,972 per QALY gained, respectively, versus no vaccine. CONCLUSIONS: Model results show RZV is potentially cost saving for the prevention of HZ in US adult HSCT recipients and US adults with selected immunocompromising conditions, and cost effective for others, supporting the use of RZV to prevent HZ and HZ-related complications in IC adults.

The potential impact of increased recombinant zoster vaccine coverage on the burden of herpes zoster among adults aged 50-59 years.

INTRODUCTION: Recombinant zoster vaccine (RZV) is recommended in the US for prevention of herpes zoster (HZ) in adults aged ≥50 years. Vaccination rates remain suboptimal for adults 50-59 years compared with adults ≥50 years overall. The objective of this study was to model changes in outcomes associated with improved RZV vaccination coverage in US adults 50-59 years. METHODS: A multicohort Markov model compared a scenario using real-world vaccination coverage for US adults 50-59 years in 2020 versus scenarios assuming higher coverage. Outcomes, based on a lifetime horizon, included HZ cases and complications avoided, quality-adjusted life-years (QALY), and costs. Model inputs included HZ epidemiology, RZV vaccine efficacy, coverage, adverse events, and costs, based on published literature and US sources. Some inputs were updated from previous models, including real-world estimates of RZV coverage, series completion, and reflecting longer-term data on waning of vaccine efficacy. The model utilized a cohort size of 42,756,488 individuals based on the 2020 US population census. RESULTS: The model projected that increasing RZV coverage in adults 50-59 years from 7.3 % to 14.6 % (to coverage for adults 60-64 years in 2020) would avoid an additional 504,468 HZ cases, 42,077 postherpetic neuralgia cases, and 56,247 cases of other HZ-associated complications. The increase in vaccine coverage would result in higher vaccination-related costs of $1,172,411,566, but the avoided HZ cases and complications would be expected to result in direct cost savings of $721,973,386 and indirect cost savings of $593,497,480 from avoided productivity loss. Overall, a gain of 5,230 discounted QALYs and cost savings of $143,059,299 from a societal perspective would be realized. CONCLUSION: Modestly higher RZV coverage in US adults 50-59 years could reduce the clinical burden associated with HZ and may result in societal cost savings. These findings demonstrate the potential value of increasing RZV vaccination in this population.

Economic and Clinical Burden of Herpes Zoster Among Patients With Inflammatory Bowel Disease in the United States.

Background: Patients with ulcerative colitis (UC) or Crohn's disease (CD) are at increased risk of herpes zoster (HZ); however, relevant cost and healthcare resource utilization (HCRU) data are limited. Methods: We estimated HCRU (hospitalization, emergency department [ED], and outpatient visits) and costs in patients with UC or CD, with and without HZ, using administrative claims data (October 2015-February 2020). HCRU and costs (2020 US dollars) were compared at 1 month, 1 quarter, and 1 year after the index date, using propensity score adjustment and generalized linear models. Results: In total, 20 948 patients were included: UC+/HZ+ (n = 431), UC+/HZ- (n = 10 285), CD+/HZ+ (n = 435), and CD+/HZ- (n = 9797). Patients with HZ had higher all-cause HCRU rates and all-cause total healthcare costs relative to those without HZ. In the first month, adjusted incidence rate ratios (aIRRs) for hospitalizations and ED visits for patients with UC and HZ compared with UC alone were 2.87 (95% confidence interval [CI], 1.93-4.27) and 2.66 (95% CI,1.74-4.05), respectively; for those with CD and HZ, aIRRs were 3.34 (95% CI, 2.38-4.70) and 3.31 (95% CI, 2.32-4.71), respectively, compared with CD alone (all P < .001). Adjusted cost differences in UC and CD cohorts with HZ over the first month were $2189 and $3774, respectively, chiefly driven by higher inpatient costs. The incremental impact on HCRU and costs in cohorts with HZ predominantly occurred during the first quarter following diagnosis. Conclusions: HZ is associated with increased HCRU and costs in patients with UC and CD, especially shortly after diagnosis.

Clinical and Economic Burden of Herpes Zoster in Patients with Rheumatoid Arthritis: A Retrospective Cohort Study Using Administrative Claims.

OBJECTIVE: To estimate the incremental healthcare resource utilization (HRU) and cost burden posed by herpes zoster (HZ) in adult patients with rheumatoid arthritis (RA) in the United States. METHODS: A retrospective cohort study was conducted using an administrative claims database containing commercial and Medicare Advantage with Part D data, between October 2015 and February 2020. Patients with RA and HZ (RA+/HZ+) or RA without HZ (RA+/HZ-) were identified based on diagnosis codes and relevant medications. Outcomes measured included HRU and medical, pharmacy, and total costs at month 1, quarter 1, and year 1 after the index date (HZ diagnosis for RA+/HZ+ cohort, randomly assigned for RA+/HZ- cohort). Generalized linear models incorporating propensity scores and other covariates were used to estimate differences in outcomes between cohorts. RESULTS: A total of 1866 patients from the RA+/HZ+ cohort and 38,846 patients from the RA+/HZ- cohort were included. Hospitalizations and emergency department visits occurred more frequently in the RA+/HZ+ than the RA+/HZ- cohort, especially in the month after HZ diagnosis (adjusted incidence rate ratio [95% confidence interval (CI)] for hospitalizations: 3.4 [2.8; 4.2]; emergency department visits: 3.7 [3.0; 4.4]). Total costs were also higher in the month after HZ diagnosis (mean adjusted cost difference [95% CI]: $3404 [$2089; $4779]), with cost differences driven by increased medical costs ($2677 [$1692; $3670]). CONCLUSIONS: These findings highlight the high economic burden of HZ among individuals with RA in the United States. Strategies to reduce the risk of HZ in patients with RA (such as vaccination) may serve to reduce this burden. Video abstract.

Public health impact of recombinant zoster vaccine for prevention of herpes zoster in US adults immunocompromised due to cancer.

Individuals who are immunocompromised (IC) due to therapy or underlying disease are at increased risk of herpes zoster (HZ). This study evaluates the public health impact of recombinant zoster vaccine (RZV) relative to no HZ vaccination for the prevention of HZ among adults aged ≥18 years diagnosed with selected cancers in the United States (US). A static Markov model was used to simulate three cohorts of individuals who are IC with cancer (time horizon of 30 years; one-year cycle length): hematopoietic stem cell transplant (HSCT) recipients, patients with breast cancer (BC; a solid tumor example), and patients with Hodgkin's lymphoma (HL; a hematological malignancy example). Cohort sizes reflect the estimated annual incidence of each condition in the US population (19,671 HSCT recipients, 279,100 patients with BC, and 8,480 patients with HL). Vaccination with RZV resulted in 2,297; 38,068; and 848 fewer HZ cases for HSCT recipients, patients with BC, and patients with HL, respectively (each versus no vaccine). Vaccination with RZV also resulted in 422; 3,184; and 93 fewer postherpetic neuralgia cases for HSCT, BC, and HL, respectively. Analyses estimated the quality-adjusted life years gained to be 109, 506, and 17 for HSCT, BC, and HL, respectively. To prevent one HZ case, the number needed to vaccinate was 9, 8, and 10, for HSCT, BC, and HL, respectively. These results suggest RZV vaccination may be an effective option to significantly reduce HZ disease burden among patients diagnosed with selected cancers in the US.

Shingles cases can be prevented by recombinant zoster vaccine (RZV). People who have a weakened immune system (immunocompromised) due to disease or therapy are more likely to develop shingles. For example, shingles occurs in nearly a quarter of patients receiving immunosuppressive treatment for blood cancers. To estimate the public health impact of vaccination against shingles in people who are immunocompromised due to cancer in the United States (US), we used a model to simulate groups with selected types of cancer. The results indicate vaccination with RZV can significantly reduce shingles cases and related complications among these groups in the US.

Incidence of Herpes Zoster in Patients With Rheumatoid Arthritis in the United States: A Retrospective Cohort Study.

OBJECTIVE: To estimate the incidence of herpes zoster (HZ) in patients with rheumatoid arthritis (RA) compared with the general population in the USA. METHODS: This retrospective, longitudinal cohort study used data from an administrative claims database containing both commercial and Medicare Advantage Part D data, with a data period from October 2015 to February 2020. Patients were aged ≥ 18 years and divided into 2 cohorts: patients with RA and patients without RA. Diagnosis and procedure codes were used to identify HZ cases and calculate incidence rates (IRs) of HZ in the 2 cohorts. Data were stratified by age group (ie, 18-49, 18-29, 30-39, 40-49, 50-64, and ≥ 65 yrs) and RA therapy type. IR ratios (IRRs), adjusted by cohort baseline characteristics, were estimated using generalized linear models to compare the incidence of HZ between cohorts. RESULTS: The overall IR of HZ was higher in the RA cohort (21.5 per 1000 person-years [PY]; N = 67,650) than in the non-RA cohort (7.6 per 1000 PY; N = 11,401,743). The highest IRs in both cohorts were observed in the age group of ≥ 65 yrs (23.4 and 11.4 per 1000 PY in the RA cohort and non-RA cohort, respectively). The overall adjusted IRR of HZ was 1.93 (95% CI 1.87-1.99, P < 0.001) for the RA cohort compared with the non-RA cohort. In the RA cohort, the highest IRs by medication class were observed in patients using corticosteroids and those using Janus kinase inhibitors. CONCLUSION: These results highlight the increased incidence of HZ in patients with RA.

Modeled impact of the COVID-19 pandemic and associated reduction in adult vaccinations on herpes zoster in the United States.

Due to COVID-19, vaccinations dropped in 2020 and 2021. We estimated the impact of reduced recombinant zoster vaccine (RZV) use on herpes zoster (HZ) cases, complications, and quality-adjusted life-year (QALY) losses among older adults. Various scenarios were compared with Markov models using data from national sources, clinical trials, and literature. Missed series initiations were calculated based on RZV distributed doses. In 2020, 3.9 million RZV series initiations were missed, resulting in 31,945 HZ cases, 2,714 postherpetic neuralgia cases, and 610 lost QALYs. Scenarios further projected disease burden increases if individuals remain unvaccinated in 2021 or the same number of initiations are missed in 2021. Health professionals should emphasize the importance of vaccination against all preventable diseases during the COVID-19 era.

Cost-benefit analysis of vaccination against four preventable diseases in older adults: Impact of an aging population.

OBJECTIVE: This exploratory study estimates the economic value of the current vaccination program and increased coverage against four preventable diseases in older adults in the United States (US). METHODS: A population-based, age-structured economic model was used to conduct a cost-benefit analysis of vaccination against influenza, pertussis, herpes zoster, and pneumococcal disease among US adults aged 50 years and older, accounting for aging of the population. The model used separate decision trees for each disease to project the discounted number of vaccinated individuals, number of disease cases, and direct medical and indirect costs (2018 US$) over a 30-year period. Benefit-cost ratios (BCRs) and net present values were calculated for two primary analyses comparing current vaccination coverage versus no vaccination and comparing increased coverage versus current coverage. Key parameter values were varied in deterministic sensitivity analyses. RESULTS: Current adult vaccination coverage (vs. no vaccination) is estimated to result in nearly 65 million averted disease cases, $185 billion averted costs of cases, and $136 billion in incremental vaccination costs over a 30-year period from a societal perspective (BCR = 1.4). Increased vaccination coverage (vs. current coverage) is associated with over 33 million additional averted disease cases, $96 billion additional averted costs of cases, and nearly $83 billion in incremental vaccination costs, resulting in a societal BCR of 1.2 over 30 years. Deterministic sensitivity analyses demonstrated that results were most sensitive to disease incidence, vaccine efficacy, and productivity costs for time required for vaccination. CONCLUSIONS: Study results highlight the economic value of vaccination programs for older adults in the US and indicate that efforts to further increase vaccination coverage may be warranted and economically justifiable.

The adult vaccination landscape in the United States during the Affordable Care Act era: Results from a large retrospective database analysis.

BACKGROUND: Early provisions of the Affordable Care Act (ACA) reduced financial barriers to preventive care, including routinely recommended vaccines; however, vaccination coverage remains suboptimal. This study examined characteristics of routine adult vaccinations and potential missed opportunities for vaccinations through the lens of healthcare resource utilization among adults in the ACA era. METHODS: This was a retrospective analysis of healthcare claims from the Truven Health MarketScan Commercial Claims and Encounters (CCAE), Medicare Supplemental (MS), and Multi-State Medicaid databases among adults aged 19 years or older. Influenza, Tdap (tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis), herpes zoster (HZ), and pneumococcal vaccinations were identified between 2011 and 2016. Potential missed opportunities were defined as well-visits at which individuals were age-eligible for vaccination but did not receive it, assessed during recommended windows for each vaccine. Missed encounters were defined as having no well-visits. Multivariable logistic regression was used to identify factors associated with vaccination and potential missed opportunities. RESULTS: Family/internal medicine and unknown/other providers administered most influenza, Tdap, and pneumococcal vaccinations, for the CCAE/MS and Medicaid cohorts, respectively. HZ vaccinations were primarily administered through pharmacies. The proportion of vaccination events increased in the pharmacy setting between 2011 and 2016. Having preventive care visits, non-well-visits, and receiving most care from a family/internal medicine practitioner were associated with increased odds of vaccination. Missed encounters were common in Medicaid enrollees. Potential missed opportunities were more prevalent in the CCAE/MS cohort than among Medicaid enrollees. Having non-well-visits was associated with a reduced likelihood of having a missed opportunity. CONCLUSION: Since the ACA implementation, preventive care among adults was sporadic. Many adults had limited opportunities for vaccination. The large prevalence of missed opportunities suggests vaccination uptake could be improved. Better support for vaccination or referrals for providers who may not traditionally vaccinate could improve vaccine uptake.

ReCAP: Treatment Patterns and Cost of Care Associated With Initial Therapy Among Patients Diagnosed With Operable Early-Stage Human Epidermal Growth Factor Receptor 2-Overexpressed Breast Cancer in the United States: A Real-World Retrospective Study.

PURPOSE: Overexpression of the human epidermal growth factor receptor 2 (HER2) protein negatively affects survival in breast cancer. This study aimed to assess real-world treatment patterns and costs associated with resected nonmetastatic HER2-positive breast cancer in the United States. PATIENTS AND METHODS: Commercially insured patients with HER2-positive breast cancer were identified from oncology registry data linked to a large US commercial administrative claims database. Treatment patterns and health care use and costs in the initial phase of care were examined. RESULTS: Among the 915 patients who met the study criteria, 662 (72%) were hormone receptor (HR) positive, and 253 (28%) were HR negative. Overall, 72% (n = 662) of patients received HER2-targeted therapy (HR positive, 69% v HR negative, 80%; P < .01), specifically trastuzumab. The most common treatment regimens, regardless of HR status, were carboplatin, docetaxel, and trastuzumab (47% of patients) during neoadjuvant therapy and carboplatin, docetaxel, and trastuzumab ± hormone therapy (30% of patients) during adjuvant therapy. Overall unadjusted cost of treatment per patient per month (HR positive, $11,906 v HR negative, $14,367; P < .001) was mainly cancer related (HR positive, $10,513 v HR negative, $13,073; P < .001). Adjusted 12-month cost was $176,779 (HR positive, $167,088 v HR negative, $180,226; P > .05). CONCLUSION: Although trastuzumab-based therapy is considered standard of care among patients with HER2-positive early-stage breast cancer, approximately 28% of these patients did not receive HER2-targeted therapy. Additional studies are warranted to examine whether patients who have not received targeted therapy are eligible for and would benefit from an HER2-targeted approach.

Adherence to 5-alpha reductase inhibitor therapy for benign prostatic hyperplasia: clinical and economic outcomes.

OBJECTIVE: Our goal was to quantify relationships between adherence to 5-alpha reductase inhibitors (5-ARIs), the risk of acute urinary retention (AUR) and prostate surgery, and medical costs related to patients with benign prostatic hyperplasia (BPH). METHODS: Claims recorded over a period of 6.5 years in a nationwide managed care database were analyzed. We conducted time-to-event multivariate analysis to evaluate relationships between adherence (medication possession ratio [MPR] thresholds of 70% or higher, 75% or higher, and 80% or higher), persistence (length of therapy), and the risk of AUR and surgery. We compared mean monthly BPH-related medical costs in patients with MPRs at or above thresholds and those with MPRs below thresholds and determined changes in BPH-related costs associated with 30-day increments of therapy. RESULTS: In AUR analyses (N = 17,293), meeting or exceeding MPR thresholds was associated with a reduced likelihood of AUR for 70% (hazard ratio [HR], 0.380), 75% (HR, 0.613), and 80% (HR, 0.519) (P < 0.05 for all). In prostate surgery analyses (N = 17,739), the likelihood of surgery was reduced with MPR thresholds of 70% or above (HR, 0.294), 75% or above (HR, 0.542), and 80% or above (HR, 0.436) (P < 0.05 for all). A longer duration of therapy was associated with a reduced likelihood of AUR (HR, 0.860) and surgery (HR, 0.884) (P < 0.05 for both). In both populations, adherence and persistence were also associated with significantly decreased BPH-related medical costs. CONCLUSION: In patients with BPH who received 5-ARI therapy, greater adherence and persistence were associated with significantly reduced risks of AUR and prostate surgery and with significantly lower medical costs. Maximizing adherence may enable patients to realize the potential long-term benefits of 5ARIs.

Evaluation of clinical outcomes with alvimopan in clinical practice: a national matched-cohort study in patients undergoing bowel resection.

OBJECTIVE: To evaluate in-hospital clinical outcomes after open and laparoscopic bowel resection (BR) with or without alvimopan treatment. BACKGROUND: Delayed return of gastrointestinal function after BR may be associated with greater postoperative morbidity and increased hospital length of stay (LOS). In clinical trials, alvimopan--a peripherally acting µ-opioid receptor antagonist--accelerated gastrointestinal recovery after open BR. METHODS: A retrospective matched-cohort study (NCT01150760) was conducted using a national inpatient database. Each alvimopan patient was exact matched (surgical procedure, surgeon specialty) and propensity score matched (baseline characteristics) to a nonalvimopan BR patient. Outcomes included gastrointestinal and other morbidity (cardiovascular, pulmonary, infection, cerebrovascular, thromboembolic); mortality; readmission rate; and intensive care unit (ICU) stay (intent-to-treat [ITT] population). Postoperative LOS and estimated cost were also compared (modified ITT population). RESULTS: Each cohort included 3525 ITT patients with similar baseline characteristics. Gastrointestinal (29.8% vs 35.7%) and other morbidity (cardiovascular [19.4% vs 24.0%], pulmonary [7.3% vs 10.5%], infectious [9.6% vs 11.8%], thromboembolic [1.2% vs 2.1%]), mortality (0.4% vs 1.0%), and mean ICU stay (0.3 vs 0.6 days) were lower in the alvimopan group (P ≤ 0.003 for each). Postoperative LOS and estimated direct cost were lower for all alvimopan patients and after laparoscopic and open BR (LOS: -1.1, -0.8, and -1.8 days respectively; cost: -$2345, -$1382, and -$3218, respectively; P ≤ 0.0008 for each). CONCLUSIONS: On average, alvimopan-treated patients had a lower incidence of mortality and most incidents of morbidities. Length of stay, ICU use, and estimated cost were also lower with comparable readmissions. These results in patients outside the clinical trial setting include laparoscopic colectomy and demonstrate a potential association between acceleration of gastrointestinal recovery and improved early postoperative outcomes.

Impact of alvimopan (entereg) on hospital costs after bowel resection: results from a large inpatient database.

PURPOSE: Delayed gastrointestinal (GI) recovery after bowel resection is associated with longer hospital stays and increased health care costs. Alvimopan (Entereg), a peripherally acting mu-opioid receptor antagonist, accelerates GI recovery after bowel-resection surgery. We undertook a study to evaluate the economic impact of alvimopan in clinical practice. METHODS: We conducted a retrospective matched cohort study using data from a large national hospital database and identified adults who had undergone small-bowel or large-bowel resection with primary anastomosis. The patients were discharged between January 1, 2009, and June 30, 2009. The surgery was performed at a hospital where alvimopan was used at least once during the study period. We matched each alvimopan patient ("user") with two controls ("non-users"). The primary outcome of total hospital costs (including the cost of alvimopan) and secondary outcomes of cost components and length of stay were compared between groups. RESULTS: The final study cohort included 480 alvimopan patients and 960 matched controls. The mean total hospital cost was $12,865 for alvimopan patients, compared with $13,905 for controls, for a difference of $1,040 (P = 0.033). There was a non-significant trend toward lower ileus-related costs between groups ($83 for alvimopan vs. $114 for controls, P = 0.086). Pharmacy and diagnostic radiology costs did not differ significantly. The mean length of stay was 5.6 days for alvimopan patients and 6.5 days for controls (P < 0.001). CONCLUSION: Patients receiving alvimopan capsules had significantly lower total hospital costs compared with controls. Along with other initiatives to improve quality and reduce costs of surgical care, alvimopan might be a good choice for use in the perioperative management of patients who undergo segmental bowel resection with primary anastomosis.

Economic analysis of alvimopan in North American Phase III efficacy trials.

PURPOSE: The economic effect of the use of alvimopan in four randomized, double-blind, placebo-controlled, Phase III, North American efficacy trials was analyzed. METHODS: Patients were eligible for the study if they were 18 years or older, were undergoing laparotomy for partial small or large bowel resection with primary anastomosis, and were scheduled for postoperative pain management with opioid-based i.v. patient-controlled analgesia. Patients analyzed in the North American Phase III trials received placebo or alvimopan 12 mg orally before surgery. Doses were administered twice daily beginning the day after surgery until hospital discharge or for a maximum of 15 doses. RESULTS: Compared with placebo, alvimopan was associated with a significantly shorter mean time to gastrointestinal (GI) recovery and a significantly shorter mean time to a written discharge order. Alvimopan was also associated with a mean hospital length of stay (LOS) of one full day less than placebo. The mean cost of alvimopan based on a mean of 8.9 12-mg doses was $558.00; the alvimopan cost at the upper limit of allowed dosing was $937.50. Combining the alvimopan and hospital costs for each patient, total costs for the alvimopan group were estimated to be lower than for the placebo group. CONCLUSION: In a post hoc analysis, alvimopan was associated with significantly faster upper and lower GI recovery after bowel resection and a mean LOS reduction of one day compared with placebo. The mean estimated hospital cost was $879-$977 less for patients who received alvimopan compared with placebo. The base-case and sensitivity analyses suggest that, on average, the use of alvimopan compared with placebo may have a cost-saving effect in the hospital setting.

Topiramate prescribing patterns among medicaid patients: diagnosis, comorbidities, and dosing.

BACKGROUND: Routine clinical practice data are useful for payers and formulary decision makers to make sound decisions regarding coverage policy. Based on a literature search, there has been scant research into topiramate prescribing patterns among Medicaid patients. OBJECTIVE: The aim of this study was to describe diagnoses, demographic characteristics, additional co-existing diagnoses, and dosing among Medicaid patients prescribed topiramate. METHODS: This descriptive, retrospective database analysis used data from South Carolina (SC) and Texas (TX) ambulatory Medicaid claims dated October 1, 2003, to December 31, 2004. Patients whose data were eligible for inclusion in the study were enrolled in Medicaid during the study period, had >or=2 topiramate prescriptions, were aged <65 years, and had evidence of a topiramate treatment-related diagnosis (possible diagnoses were identified through literature search and drug compendiums). Four cohorts were defined: (1) epilepsy only; (2) migraine only; (3) epilepsy and migraine; and (4) nonepilepsy/nonmigraine. Demographic characteristics, diagnoses, comorbidities, and daily dose of topiramate were summarized using descriptive statistics. The initial study analysis (period 1) was a 180-day window comprising the 90 days before and after the first available topiramate prescription claim was filed. A second, 360-day analysis (period 2) was completed comprising the 180 days before and after the index topiramate prescription date. RESULTS: In the 180-day analysis, 2216 SC and 4766 TX Medicaid patients met the selection criteria. Cohort classification percentages were 32.3% and 39.6% (epilepsy only), 29.7% and 16.4% (migraine only), 10.7% and 9.2% (epilepsy and migraine), and 27.3% and 34.9% (nonepilepsy/nonmigraine) for SC and TX, respectively. Mean (SD) ages were 29.9 (15.9) (SC) and 27.1 (16.1) (TX) years. In the nonepilepsy/nonmigraine cohort, the most common diagnoses were bipolar disorder and depression. The median daily doses in the epilepsy-only cohort were 175 mg/d in the SC group and 200 mg/d in the TX group. In the migraine-only cohort, the median daily dose was 100 mg/d in SC and TX. Results for the 360-day analysis were similar. CONCLUSIONS: In this descriptive study using data from 2 Medicaid populations, the majority of patients using topiramate had a diagnosis of epilepsy and/or migraine. Median dosages ranged from 175 to 200 mg/d in patients with epilepsy and 100 mg/d in those with migraine. Depression was a common comorbidity in the migraine cohort and the nonepilepsy/nonmigraine cohort.